Low porosity solid electrolyte membrane and method for manufacturing the same

ABSTRACT

An improved, low porosity, solid electrolyte membrane and a method of manufacturing the solid electrolyte membrane are provided. The low porosity, solid electrolyte membrane significantly improves both mechanical strength and porosity of the membrane, inhibits the growth of lithium dendrites (Li dendrites), and thereby maintains and maximizes electrochemical stability of an all-solid-state battery. This is accomplished by wet-coating a sulfide or oxide solid electrolyte particle with a thermoplastic resin, or a mixture of the thermoplastic resin and a thermosetting resin, using a solvent to prepare a composite and hot-pressing the composite at a relatively low temperature and at a low pressure.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 15/843,631, filed Dec. 15, 2017, which claims under 35 U.S.C. §119(a) the benefit of and priority to Korean Patent Application No.10-2016-0172370 filed on Dec. 16, 2016, the entire contents of which areincorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to an improved low porosity solidelectrolyte membrane which significantly improves both mechanicalstrength and porosity, inhibits growth of lithium dendrites (Lidendrites), and thereby maintains and maximizes electrochemicalstability of an all-solid-state battery. This is accomplished bywet-coating a sulfide or oxide solid electrolyte particle with athermoplastic resin or a mixture of the thermoplastic resin and athermosetting resin using a solvent to prepare a composite andhot-pressing the composite at a relatively low temperature and at a lowpressure.

Background Art

An all-solid-state battery, which is a lithium secondary battery using asolid electrolyte, is a potential candidate for next-generationsecondary batteries, which is expected to satisfy both stability andenergy density needs, particularly in the automotive industry. In anall-solid-state battery, a solid electrolyte is disposed between apositive electrode and a negative electrode and a current collector islinked to each electrode.

However, like a conventional commercially-available liquidelectrolyte-based lithium secondary battery, the all-solid-state batterycannot control the formation of lithium dendrites during thecharge/discharge cycles, which may disadvantageously result in a shortcircuit. When dendrite formation can be controlled in theall-solid-state battery, a high energy density all-solid-state batterycan be produced, which serves as a desirable alternative tocommercially-available lithium secondary batteries.

Conventional production methods result in porous solid electrolytemembranes that permit dendrite formation and thus result in shortcircuits. In addition, conventional production methods requirehot-pressing the solid electrolyte at high temperatures and thusincreases the difficulty and cost of the process.

Thus, there is a need for technologies that can inhibit formation oflithium dendrites—a common problem in all-solid-state batteries using alithium negative electrode.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known to a person of ordinary skill in the art.

SUMMARY

The present disclosure addresses the above-described problems associatedwith the prior art.

According to the example embodiments described in greater detail herein,when a solid electrolyte membrane is produced by preparing a compositeof a solid electrolyte particle and a thermoplastic resin (thermoplasticpolymer) and hot-pressing the composite under certain conditions,porosity of the electrolyte membrane is greatly improved, formation oflithium dendrites is inhibited, and cell cycle (life) is thus improved.

Accordingly, in one aspect, the present disclosure provides a solidelectrolyte membrane which can inhibit formation of lithium dendritesbased on controlled pore formation.

In another aspect, the disclosure provides a method of manufacturing thesolid electrolyte membrane.

In an example embodiment, a solid electrolyte membrane is obtained byhot-pressing a sulfide or oxide solid electrolyte particle coated with apolymer film, wherein the polymer film comprises at least onethermoplastic resin selected from the group consisting of polymethylmethacrylate (“PMMA”), polystyrene (“PS”) and polyester resins, or amixture of the thermoplastic resin with at least one thermosetting resinselected from acrylonitrile-butadiene rubber (“NBR”), an epoxy resin andan unsaturated ester resin. In an alternative embodiment, thecombination of these compounds may also include a cross-linkablecompound or a reaction product thereof.

In another example embodiment, a method of manufacturing a solidelectrolyte membrane includes: (a) mixing a sulfide or oxide solidelectrolyte particle with a thermoplastic resin, or a mixture of thethermoplastic resin and a thermosetting resin, and a solvent capable ofdissolving the resin and wet-coating the resulting mixture; (b) removingthe solvent by drying to prepare a solid electrolyte composite; and (c)hot-pressing the solid electrolyte composite to produce a solidelectrolyte membrane.

Other aspects and example embodiments are discussed below.

BRIEF DESCRIPTION OF THE FIGURES

The above and other features of the present disclosure will now bedescribed in detail with reference to certain example embodimentsthereof as shown in the accompanying drawings described hereinbelow, andwhich are provided by way of illustration only, and thus are notlimitative of the present invention, and wherein:

FIG. 1 is a schematic diagram illustrating a conventional solidelectrolyte membrane experiencing lithium dendrite formation;

FIG. 2 is a schematic diagram illustrating an example embodiment of animproved solid electrolyte membrane in accordance with the disclosure;

FIG. 3 is a graph showing porosity of the solid electrolyte membrane asa function of polymer weight in an example embodiment;

FIG. 4 is a graph illustrating voltage as a function of capacity, anddemonstrating inhibition of lithium dendrite formation using an exampleembodiment of the improved solid electrolyte membrane according to thepresent disclosure;

FIG. 5 is a graph illustrating cell performance testing results as afunction of the thermoplastic resin, hot-pressing and current;

FIG. 6 is a graph illustrating voltage as a function of capacity for arange of thermoplastic resin amounts used in an example embodiment ofthe improved solid electrolyte membrane according to the presentdisclosure;

FIG. 7 is a graph showing porosity as a function of pressure in anexample embodiment of the improved solid electrolyte membrane accordingto the present disclosure;

FIG. 8 is a graph showing porosity as a function of temperature in anexample embodiment of the improved solid electrolyte membrane accordingto the present disclosure;

FIG. 9 is a graph showing porosity as a function of the amount ofthermosetting resin added in an example embodiment of the improved solidelectrolyte membrane according to the present disclosure; and

FIG. 10 shows results of cell performance testing depending on theamount of thermosetting resin added in an example embodiment of theimproved solid electrolyte membrane according to the present disclosure.

It should be understood that the appended drawings are not necessarilyto scale, presenting a somewhat simplified representation of variouspreferred features illustrative of the basic principles of theinvention. The specific design features of the present invention asdisclosed herein, including, for example, specific dimensions,orientations, locations, and shapes will be determined in part by theparticular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent partsof the present disclosure throughout the several figures of the drawing.

DETAILED DESCRIPTION

Hereinafter, various example embodiments are described in detail inconjunction with the accompanying drawings. It will be understood thatthe present description is not intended to limit the invention to thoseexample embodiments. On the contrary, the invention is intended to covernot only the example embodiments, but also various alternatives,modifications, equivalents and other embodiments, which may be includedwithin the spirit and scope of the invention as defined by the appendedclaims.

FIG. 1 is a schematic diagram illustrating the structure of aconventional solid electrolyte membrane, as assembled into a battery. Ina conventional method for making the solid electrolyte membrane, a solidelectrolyte membrane is produced by compressing sulfide or oxide solidelectrolyte particles at a high pressure and at a high temperature. Inthis process, a large number of pores are formed, and lithium dendritesform in the pores of the electrolyte membrane during batterycharge/discharge cycles. Because of lithium dendrite formation,disadvantageously, short circuits readily occur. In addition, thismethod for producing the conventional solid electrolyte membrane islimited in its ability to control certain physical properties of themembrane, such as brittleness. Moreover, manufacturing a solidelectrolyte membrane at a relatively high temperature (e.g. 200° C. orhigher) is more difficult and costly in commercial settings.

The present disclosure addresses these issues by providing anelectrolyte membrane formed by wet-coating a sulfide or oxide solidelectrolyte particle with a thermoplastic resin, or a mixture of thethermoplastic resin and a thermosetting resin, to prepare a solidelectrolyte composite and then hot-pressing the solid electrolytecomposite. Wet-coating using a thermoplastic resin, or a mixture of thethermoplastic resin and a thermosetting resin, advantageously allowshot-pressing at a relatively low temperature of 100° C. In addition,dendrite formation of dendrites is inhibited during cellcharge/discharge cycles due to the controlled porosity of the solidelectrolyte membrane, and cell cycle (life) is thus significantlyimproved.

The thermoplastic resin preferably includes one or more compoundsselected from the group consisting of PMMA, PS and polyester resins. Inaddition, the thermosetting resin preferably includes one or morecompounds selected from the group consisting of an NBR, an epoxy resinand an unsaturated ester resin, and monomers thereof. The thermoplasticand thermosetting resins may include all candidates that can bedissolved in a non-polar solvent or the like that has no or minimumreactivity with a sulfide solid electrolyte.

While the thermoplastic resin may be used alone, physical propertiessuch as brittleness can be improved when it is used in combination witha thermosetting resin.

In embodiments where the thermoplastic resin is used alone without athermosetting resin, the solid electrolyte membrane comprises from about70 to about 98% by weight of the sulfide or oxide solid electrolyteparticle and from about 2 to about 30% by weight of the thermoplasticresin, more preferably, from about 2 to about 20% by weight. When thethermoplastic resin is used in an amount less than 2% by weight, it isdifficult to control the porosity of the membrane, and when thethermoplastic resin is used in an amount exceeding 30% by weight, it isdifficult to achieve low ionic conductivity.

In embodiments where the thermoplastic resin is used in combination witha thermosetting resin, the solid electrolyte membrane comprises fromabout 65 to about 97% by weight of the sulfide or oxide solidelectrolyte particle, from about 2 to about 30% by weight of thethermoplastic resin, and from about 1 to about 5% by weight of thethermosetting resin. When the thermosetting resin is used in an amountless than 1% by weight, there is limited improvement of the physicalproperties of the thermoplastic resin, and when the thermosetting resinis used in an amount exceeding 5% by weight, there is difficultycontrolling the formation of pores due to the influence of thethermosetting resin on the physical properties of the thermoplasticresin. Preferably, the thermosetting resin is used in an amount of fromabout 2 to about 20% by weight.

Representative non-limiting examples of the sulfide solid electrolyteparticle according to the present disclosure include Li₃PS₄ andcompounds having a composition of aLi₂S-b(GeS₂)-cP₂S₅-dLiX, where X is ahalide element such as Cl, Br, or I (e.g. Li₁₀GeP₂S₁₂). A solidelectrolyte having a composition of iodine-substituted Li₆PS₅Cl may alsobe used. In addition, any other well-known solid electrolyte may be usedwithout limitation.

Hot-pressing is preferably conducted at a temperature of from about 100to about 240° C. (i.e. at a temperature equal to or higher than theglass transition temperature and lower than the melting point of thethermoplastic resin), and at a pressure of from about 200 to about 500Mpa. For greater efficiency, hot-pressing is preferably conducted at atemperature of from about 100 to about 220° C. and a pressure of formabout 200 to about 400 Mpa. These conditions are determined byconsidering the physical properties of the thermoplastic resin. Anexample is shown in the Test Example described later.

The present disclosure also provides a method of manufacturing a solidelectrolyte membrane comprising the steps of: (a) mixing a sulfide oroxide solid electrolyte particle with a thermoplastic resin, or amixture of the thermoplastic resin and a thermosetting resin, and asolvent capable of dissolving the resin, and wet-coating the resultingmixture, (b) removing the solvent by drying to prepare a solidelectrolyte composite and (c) hot-pressing the solid electrolytecomposite to produce a solid electrolyte membrane.

The thermoplastic resin preferably includes one or more compoundsselected from the group consisting of PMMA, PS and polyester resins. Inaddition, the thermosetting resin preferably includes one or morecompounds selected from the group consisting of an NBR, an epoxy resinand an unsaturated ester resin, and monomers thereof. The thermoplasticand thermosetting resins may include all candidates that can bedissolved in a non-polar solvent or the like that has no or minimumreactivity with a sulfide solid electrolyte.

In step (a), in embodiments where the thermoplastic resin is used alonewithout a thermosetting resin (i.e. where the composition comprises fromabout 70 to about 98% by weight of the sulfide or oxide solidelectrolyte particle and from about 2 to about 30% by weight of thethermoplastic resin, and the total weight percent of the composition isconsidered as 100 parts by weight), the solvent can be used in an amountof from about 10 to about 100 parts by weight, but is preferably fromabout 30 to about 50 parts by weight to maximize the uniformity of thecoating. The solvent includes one or more non-polar solvents selectedfrom the group consisting of toluene and xylene, and dissolves only thethermoplastic or thermosetting resin while not reacting with the solidelectrolyte particle.

When the thermoplastic resin is used in combination with thethermosetting resin (i.e. the composition comprises from about 65 toabout 97% by weight of the sulfide or oxide solid electrolyte particle,from about 2 to about 30% by weight of the thermoplastic resin and fromabout 1 to from about 5% by weight of the thermosetting resin, and thetotal weight percent of the composition is considered as 100 parts byweight), in step (a), the solvent is used in an amount of from about 10to about 100 parts by weight but is preferably from about 30 to about 50parts by weight for maximizing uniformity of coating.

The hot-pressing of step (c) is conducted at a temperature of from about100 to about 240° C. (i.e. a temperature equal to or higher than theglass transition temperature and lower than a melting point of thethermoplastic resin), and at a pressure of from about 200 to about 500Mpa.

Using a thermoplastic resin and a thermosetting resin in the solidelectrolyte membrane and the method of manufacturing the same asdescribed by reference to the example embodiments in the presentdisclosure results in the electrolyte membrane having a low porosity.This inhibits the formation of lithium dendrites, suppresses thegeneration of short circuits, offers electrochemically stable operationof cells, enables manufacture at low process temperatures advantageousfor commercial settings, and easily provides an all-solid-state batterywith a high energy density.

Examples of the embodiments described above, and test results usingthose embodiments, are provided below. However, the examples areprovided only for illustrative purposes and the scope of the disclosureis not limited to the examples.

Comparative Example and Example: Production of Solid ElectrolyteMembrane

In accordance with the composition and content shown in the followingTable 1, solid electrolyte particles were wet-coated. Then, the solidelectrolyte particles were dried at a high temperature (i.e. the boilingpoint or higher of the solvent) and under vacuum to prepare a solidelectrolyte composite. The solid electrolyte composite was hot-pressedat a temperature of 105° C. and at a pressure of 200 Mpa to produce asolid electrolyte membrane. As a control group, a solid electrolytemembrane on which hot-pressing was not conducted was also produced.

Test Example 1: Measurement of Thickness, Ionic Conductivity andPorosity

The thickness, conductivity and porosity of solid electrolyte membranesproduced in Comparative Example and Example were measured and theresults are shown in the following Table 1. FIG. 3 is a graph showingthe porosity variation depending on the amount of thermoplastic resinused in the electrolyte composite.

TABLE 1 Solid electrolyte Thermoplastic Solvent* particle resin (partsby Hot Thickness Conductivity Porosity Item (% by weight) (% by weight)weight) pressing (μm) (S/cm) (%) Comparative Li₆PS₃Cl — X X 730 3.80 ×10⁻³ 16.80 Example 1 (100% by weight) Comparative Li₆PS₃Cl — X X 8003.65 × 10⁻³ 23.76 Example 2 (100% by weight) Comparative Li₆PS₃Cl PMMA100 X 720 3.18 × 10⁻³ 14.33 Example 3 (98% by weight) (2% by weight)Example 1 Li₆PS₃Cl PMMA 100 ◯ 680 3.40 × 10⁻³ 9.29 (98% by weight) (2%by weight) Comparative Li₆PS₃Cl NBR 100 X 770 1.72 × 10⁻³ 19.90 Example4 (98% by weight) (2% by weight) Example 2 Li₆PS₃Cl NBR 100 ◯ 760 2.89 ×10⁻³ 18.84 (98% by weight) (2% by weight) Comparative Li₆PS₃Cl PS 100 X730 2.40 × 10⁻³ 13.60 Example 5 (95% by weight) (5% by weight) Example 3Li₆PS₃Cl PS 100 ◯ 680 2.81 × 10⁻³ 7.25 (95% by weight) (5% by weight)Comparative Li₆PS₃Cl PMMA 100 X 740 2.20 × 10⁻³ 13.26 Example 6 (90% byweight) (10% by weight) Example 4 Li₆PS₃Cl PMMA 100 ◯ 680 2.33 × 10⁻³5.61 (90% by weight) (10% by weight) Comparative Li₆PS₃Cl PS 100 X 7302.40 × 10⁻³ 12.40 Example 7 (80% by weight) (20% by weight) Example 5Li₆PS₃Cl PS 100 ◯ 680 2.81 × 10⁻³ 3.10 (80% by weight) (20% by weight)Comparative Li₆PS₃Cl PS 100 X 720 2.40 × 10⁻³ 11.20 Example 8 (70% byweight) (30% by weight) Example 6 Li₆PS₃Cl PS 100 ◯ 680 2.81 × 10⁻³ 3.02(70% by weight) (30% by weight) *represents the amount of a solventobtainable when the total weight percent of a combination of the solidelectrolyte particle and the thermoplastic resin is considered as 100parts by weight

As can be seen from Table 1 and FIG. 3, when hot-pressing is conductedusing a solid electrolyte particle, and PMMA or PS as the thermoplasticresin, conductivity is improved and porosity is reduced as compared tothe control samples where no hot-pressing was used. However, it can beseen that addition of an NBR thermosetting resin exerts limited controlon porosity. This suggests that the thermoplastic resin and hot-pressingare essential factors in controlling the formation of pores in thesulfide solid electrolyte.

Test Example 2: Confirmation of Inhibition of Formation of LithiumDendrites

Performance testing (current: 0.2 C) was conducted on a cell includingTiS₂ as a positive electrode and an Li metal negative electrode(TiS₂:LPS=1:2), and having 150 mg of LPS as an electrolyte layer, or asolid electrolyte membrane according to Example 1. For purposes of thisexample, LPS is defined as 75Li₂S-25P₂S₅-based glass-ceramic. LPS (400mesh) means a very fine particle screened on 400 mesh and LPS (400mesh-X) means a very large particle not screened on 400 mesh. Testresults are shown in FIG. 4.

As can be seen from FIG. 4, the cell including the solid electrolytemembrane of Example 1 does not short-circuit, whereas all of theconventional cells using LPS and not including the solid electrolytemembrane of Example 1 short-circuit.

Test Example 3: Cell Performance Testing

In order to ascertain the influences of the thermoplastic resin,hot-pressing and current on inhibition of lithium dendrites, cycle lifewas measured on all-solid-state batteries including the solidelectrolyte membranes produced in Comparative Example and Example shownin Table 1 and the results are shown in FIG. 5.

As can be seen from FIG. 5, the cell including the solid electrolytemembrane of Example 1 exhibits a considerably improved cycle life of 20or more at a current of 0.2 C.

Test Example 4: Cell Performance Testing as a Function of the Amount ofThermoplastic Resin Used

Performance testing (current: 0.2 C) was conducted on cells includingTiS₂ as a positive electrode and an Li metal negative electrode(TiS₂:LPS=1:2), and including the solid electrolyte membranes ofExamples 1 and 4, and the solid electrolyte membranes of Examples 7 and8. Examples 7 and 8 were prepared as in Example 1, except that PMMA isused in an amount of 20% by weight in Example 7 and 30% by weight inExample 8. Test results are shown in FIG. 6.

As can be seen from FIG. 6, as the percentage (%) by weight of PMMAincreases, over-voltage of cell performance is observed. This means thatthe ionic conductivity of the solid electrolyte composite decreases. Thepreferred amount of PMMA defined in the present invention is from about5 to about 20% by weight and the optimum weight of the thermoplasticresin may be varied depending on the composition and particle size ofthe solid electrolyte.

Accordingly, the amount of thermoplastic resin used is preferably fromabout 2 to about 30% by weight, more preferably from about 2 to about20% by weight.

Test Example 5: Pressure Effects

For the solid electrolyte membrane of Example 9 (prepared as in Example1, except that PMMA is used in an amount of 5% by weight), porosity wasmeasured at different pressures using a press through the pelletthickness and density of the solid electrolyte. Test results are shownin FIG. 7.

As can be seen from FIG. 7, when hot-pressing is conducted at a pressureof from about 200 to about 500 Mpa, porosity of the electrolyte membranedecreases. For optimum efficiency, the pressure used should bepreferably from about 200 to about 400 Mpa.

Test Example 5: Temperature Effects

The porosity of the solid electrolyte membrane of Example 3 was measuredat different temperatures using hot-press equipment and test results areshown in FIG. 8.

As can be seen from FIG. 8, when hot-pressing is conducted at atemperature of from about 100 to about 240° C., and more preferably fromabout 100 to about 220° C., the porosity of the electrolyte membranedecreases. For optimum effects, the temperature used in manufacturingthe improved electrolyte membranes according to the disclosure ispreferably greater than or equal to the glass transition temperature(T_(g)) of the thermoplastic resin and is less than or equal to themelting point (T_(m)) of the thermoplastic resin.

Test Example 6: Porosity and Cell Performance Testing as a Function ofthe Amount of Thermosetting Resin Added

In accordance with the composition and content shown in the followingTable 2, the solid electrolyte particle was wet-coated. The solidelectrolyte particle was dried under the same conditions as in Exampleto prepare a solid electrolyte composite, and the solid electrolytecomposite was hot-pressed at a temperature of 105° C. and at a pressureof 200 Mpa to produce a solid electrolyte membrane.

TABLE 2 Solid electrolyte Thermoplastic Thermosetting Solvent* particleresin resin (parts by Hot Thickness Conductivity Porosity Item (% byweight) (% by weight) (% by weight) weight) pressing (μm) (S/cm) (%)Example 3 Li₆PS₃Cl PS — 100 ◯ 680 2.81 × 10⁻³ 7.25 (95% by weight) (5%by weight) Example 10 Li₆PS₃Cl PS Epoxy 100 ◯ 680 2.60 × 10⁻³ 7.51 (95%by weight) (5% by weight) (1% by weight) Example 11 Li₆PS₃Cl PS Epoxy100 ◯ 690 1.40 × 10⁻³ 8.03 (95% by weight) (5% by weight) (3% by weight)Example 12 Li₆PS₃Cl PS Epoxy 100 ◯ 720 8.70 × 10⁻⁴ 9.56 (95% by weight)(5% by weight) (5% by weight) Comparative Li₆PS₃Cl PS Epoxy 100 ◯ 7606.20 × 10⁻⁴ 12.4 Example 9 (95% by weight) (5% by weight) (10% byweight) *represents the amount of a solvent obtainable when the totalweight percent of a combination of the solid electrolyte particle, thethermoplastic resin, and the thermosetting resin is considered as 100parts by weight.

For the solid electrolyte membranes prepared in Example 3, and Examples10 to 13, porosity was measured using a press through the pelletthickness and density of the solid electrolyte. Test results are shownin FIGS. 9 and 10.

As can be seen from FIGS. 9 and 10, when the thermosetting resin is usedin an amount of from about 1 to about 5% by weight, with respect to theweight of the thermoplastic resin, low porosity of the electrolytemembrane is achieved.

Accordingly, the example embodiments of the polymer electrolytemembranes as described in the present disclosure, which are manufacturedby wet-coating a sulfide or oxide solid electrolyte particle with fromabout 2 to about 30% by weight of a thermoplastic resin and from about 1to about 5% by weight of a thermosetting resin, and hot-pressing theresulting solid electrolyte particle at a low temperature and at a lowpressure, reduce the porosity of the electrolyte membrane, therebyinhibiting the formation of lithium dendrites and providing a stablyoperated all-solid-state battery.

As apparent from the foregoing, the solid electrolyte membrane describedherein achieves reduced porosity by using a thermoplastic resin, therebyinhibiting the generation of short circuits, allowing cells to stablyelectrochemically operate, preventing the formation of lithium dendritesto improve cell cycle life, and easily providing an all-solid-statebattery with a high energy density. In addition, because the membranecan be manufactured at low process temperatures, the manufacturingprocess is less costly.

The invention has been described in detail with reference to preferredembodiments thereof. However, it will be appreciated by those skilled inthe art that changes may be made in these embodiments without departingfrom the principles and spirit of the invention, the scope of which isdefined in the appended claims and their equivalents.

The invention claimed is:
 1. A solid electrolyte membrane comprising asolid electrolyte particle coated with a polymer film, wherein thepolymer film comprises at least one thermoplastic resin; wherein thepolymer film further comprises at least one thermosetting resin; andwherein the solid electrolyte membrane comprises: from about 65% toabout 97% by weight of the solid electrolyte particle; from about 2% toabout 30% by weight of the thermoplastic resin; and from about 1% toabout 5% by weight of the thermosetting resin.
 2. The solid electrolytemembrane of claim 1, wherein the solid electrolyte membrane ishot-pressed.
 3. The solid electrolyte membrane of claim 1, wherein thesolid electrolyte particle is a sulfide or an oxide solid electrolyteparticle.
 4. The solid electrolyte membrane of claim 1, wherein thethermoplastic resin is selected from the group consisting of polymethylmethacrylate, polystyrene and polyester resins.
 5. The solid electrolytemembrane of claim 1 wherein the thermosetting resin is selected from thegroup consisting of an acrylonitrile-butadiene rubber, an epoxy resinand an unsaturated ester resin.
 6. The solid electrolyte membrane ofclaim 2, wherein the hot-pressing is carried out at a temperaturegreater than or equal to the glass transition temperature of thethermoplastic resin and at a pressure of from about 200 to about 500Mpa.
 7. The solid electrolyte membrane of claim 6, wherein thehot-pressing is carried out at a temperature of from about 100 to about240° C.
 8. The solid electrolyte membrane of claim 6, wherein thehot-pressing is carried out at a temperature less than or equal to themelting point of the thermoplastic resin.